qubit

noun

qu·​bit ˈkyü-bət 

plural qubits

: a unit of computing information that is represented by a state of an atom or elementary particle (such as the spin) and can store multiple values at once due to the principles of quantum mechanics

And the most basic truth of quantum mechanics dictates that you cannot measure a qubit without destroying the superposition. The register that said 1 and 0 will randomly collapse into 1 or 0.

—George Johnson

compare bit entry 3 sense 1

Examples of qubit in a Sentence

Recent Examples on the Web

This means that two qubits can hold four values at once. —Cade Metz, New York Times, 19 Feb. 2025

Its behavior is described by quantum mechanics, allowing it to be used as a qubit. —John Timmer, Ars Technica, 19 Feb. 2025

Unlike today’s internet, which sends data as either a 0 or a 1, quantum internet relies on quantum bits, or qubits, which can exist as both 0 and 1 at the same time. —Kurt Knutsson, Cyberguy Report, FOXNews.com, 14 Apr. 2025

Unlike classical computing, which processes information through bits that can exist in either zeros or ones, quantum computing is an evolving field where quantum bits (or qubits) can occupy both zero and one in a single unit. —Rachel Curry, CNBC, 6 Apr. 2025

Word History

Etymology

qu- (in quantum entry 2) + bit entry 4, probably formed with punning allusion to cubit

Note: According to the American physicist Benjamin Schumacher, in the acknowledgements to a paper ("Quantum coding," Physical Review A, vol. 51, issue 4 [April, 1995], p. 2747), "The term 'qubit' was coined in jest during one of the author's many intriguing and valuable conversations with W. K. Wootters, and became the initial impetus for this work."

First Known Use

1994, in the meaning defined above

Rhymes for qubit

• cubit